1. Technical Field
This invention relates to moldboard plows and particularly to a moldboard plow suitable for both low and high speed plowing.
2. Prior Art
Heretofore, considerable effort has been expended toward providing a variable speed plow which may be adjusted to permit more effective plowing at different travel speeds. As is well known in the art, when a low speed plow is pulled at high speed, there is a tendency for the plow to throw the ground being plowed an excessive distance. When a plow designed for high speed operation is operated at a slow speed, such as when slowing to make the turn at the end of the land being plowed, the plow may not do a good job of covering crop residue. One attempt to provide a variable speed plow is illustrated in a prior art publication wherein the entire plow bottom is pivoted about a vertical pivot located centrally in relation to the plow bottom. This plow has the disadvantage in that the share of the plow is pivoted, as well as the moldboard, thereby changing the point position and the width of the cut of the share. Another prior art publication shows a construction wherein the entire plow bottom is pivoted about the vertical pivot in response to plowing speed. In this last-mentioned construction, a disadvantage arises in that the land side of the plow is pushed into the sidewall of the furrow thereby increasing the energy required for moving the plow through the ground. In U.S. Pat. Nos. 2,326,097 and 247,110, the rear portion of the moldboard is pivoted about an axis lying substantially in the planes of the respective moldboards. In U.S. Pat. No. 255,898, the upper part of the moldboard is pivotable about a vertical axis near the land side of the plow.